Feeding and ejecting device for centerless grinders



Dem J. E. HECKETHORN 2,412,730

E FOR CENTERLESS GRINDERS FEEDING AND EJECTING DEVIC Filed July 7, 1945 2 Sheets-Sheet l INVENTOR. joH/v, [am 1400 f/zcmsn/ofi/v.

ATTORNEY.

ERS

J. E. HECKETHORN FEEDING AND EJECTING DEVICE FOR CENTERLESS GRIND Filed July 7, 1945 2 Sheets-Sheet 2 Patented Dec. 17, 1946 31 PATENT OFFICE FEEDING AND EJECTING DEVICE FOR 4 CENTERLESS GRINDERS 3 Claims.

- 1 This invention relates to an automatic infeed and ejecting attachment for centerless grinding machines and is designed more particularly as an improvement over the invention illustrated in copending application Serial No. 497,102, now Patent Number 2,379,961.

The principal object of this invention is to provide a simple and highly eflicient pneumaticallyoperated mechanism for automatically placing workpieces in a centerless grinding machine and removing the finished pieces therefrom.

Another object of the invention is to so construct the device that it will operate synchronously with the advance and withdrawal of the feed wheel of a conventional centerless grinding machine.

A still further object is to provide a device of,

numerals refer to like parts in all views of the drawings and throughout the description.

In the drawings:

Fig. 1 is a side view of a typical centerless grinding machine, illustrating the elements of the invention in place thereon;

Fig. 2 is an enlarged, longitudinal section through the work ejecting mechanism employed in the improved attachment;

Fig. 3 is a detail, cross-section, taken on the line 3-3, Fig. 6;

Fig. 4 is a similar line 4-4, Fig. 2;

Fig. 5 is a similar cross-section taken on the line 55-45, Fig. 6;

Fig. 6 is an enlarged cross-section through the grinding machine illustrating the attachment in place thereon; taken on the line 66, Fig. 1;

. Fig. '7 is a detail View illustrating a valve operating cam employed in the attachment;

Fig. 8 is a detail view illustrating a face viewof the valve operated by the cam of 1;

Fig. 9 is a side view of the valve of Fig. 8; and

Fig. 10 is a cross-section through the valve of Fig. 9.

Standard parts of a typical centerless grinding machine are designated on the drawings by cross-section taken on the numeral as follows: bed HJ', grinding wheel H, feed wheel l2, feed wheel motor housing [3, feed wheel carriage I 4, feed wheel carriage feed screw l5, feed wheel feed sleeve 16, hand wheel 11, grinding wheel motor I 8, grinding wheel housing l9, work rest 20, work rest holder 2|, lower slide 22, ejection plunger 23, and work pieces 54.

In such a machine the work being ground rests upon the work rest 20 between the grinding wheel l land the feed wheel l2. The feed screw I5 is rotated by means of the hand wheel l1,'to bring the feed wheel carriage l4 adjacent the work. The feed sleeve I 6 is then rotated on the feed screw to move the carriage l4 forwardly fora. present distance sufficient to bring the work to the required finished diameter. Therefor the amount of rotation of the feed sleeve l6 determines the amount of grinding which will be done and the sleeve must be circumferentially reciprocated a preset distance for each article to be ground. The wear of the grinding wheel is adjusted durin operation by rotation of the hand wheel l1. This invention is designed to automatically place the work pieces 54 between the wheels ll and I2; rotate the feed sleeve It at the proper speed'and for the proper distance to bring the workpiece to the acquired finished diameter; then withdraw the feed wheel l2 by return reciprocation of the feed sleeve l6; and eject the finished work piece from between the wheels III and It. With the exception of the grinding wheel I I, only the parts added to the standard centerless grinder are shown shaded in the drawings. The unshaded parts will be found in all standard machines.

The mechanism for reciprocating the feed sleeve I 6 is shown and described in detail in the said copending application, Serial No. 497,102.,

In this invention the same mechanism is used and I will be but briefly described herein as follows:

A base plate 24 is mounted on the motor housing l3 and carries an operating motor 25 which, through the medium of a V-belt 26 and a speed reducer 21, rotates a cam shaft 28. The shaft 28 projects from both faces of the speed reducer and on the front face terminates in a large cam member 29 provided with a face cam track. A rocker arm 30 is journalled in suitable hearings on the plate 23 and projects both above and below the latter. The upper extremity of the rocker arm terminates in a cam follower 3! which follows the face cam in the member 29 to impart a reciprocatory movement to the rocker arm 30. The lower part of the rocker arm 30 is connected to a crank member 32 on the feed sleeve l6. Thus, at each plied to the valve housing 7 return 'pipe 43 to one i l6 will be rotated forward and back to move the feed wheel |2 toward the work piece and away therefrom.

The present invention makes use of the cam shaft 28 for timing its operation so that the infeed and ejection of the work pieces will be in synchronism with the movements of the rocker arm 30.

The present invention employs a valve cam 33 mounted on the cam shaft 28. A two-way value housing 34 is mounted in a valve bracket 35 secured to the base plate 24 opposite and below the cam 33. The valve housing contains a valve plug 36 having a stem 31 projecting from the housing 34. The stem terminates in a valve oper-- ating lever 38 carrying a roller 39 in the path of the cam 33. Thus, as the cam rotates in a counter-clockwise direction in the roller 39 causing the lever 38 to rotate the valve plug 36 90. When the 08111;"33 leaves the roller 39 a spring 40 will'return the lever 88 to its former position.

Compressed air from any suitable source is sup- 34 through a compressed air pipe 4| and flows from and to the housing through a feed pipe 42 and a return pipe 43, respectively. 'The housing is also provided with exhaust ports 44. The valve is a conventionaltwo-way type, that is,'when the plug is rotated in one direction it will connect the feed pipe 42 with th compressed air pipe 4| and the of the exhaust ports 44. When the plug is rotated in the other direction it will connect the return pipe 43 with the compressed air pipe 4| and the feed pipe 42 with one of the exhaust ports 44. The feed pipe 42 is connected with the outer extremities of an infeed cylinder 45 and an ejection cylinder 46 through the medium of flexible hoses 41, and the return pipe 43 is connected with the inner extremity of these two cylinders by means of similar hoses 48.

The infeed cylinder 45 is supported in an .inverted channel arm 49 which in turn is supported from the work rest holder 2| in a suitable bracket 50. The bracket 50 also supports a slide track bar (see Fig. 5), along which, a pusher block 52 travels, and a work piece magazine 53 containing a vertical pile of unfinished work pieces 54. The pusher block is designed to-push the lowermost work piece 54 from the pile inwardly along a projecting floor member 55 until it falls bygravity to the work rest 20.

The cylinders 45 and 46 are standard actuating cylinders which may be purchased on the open market and contain a suitable piston (not shown) for actuating a projecting piston rod 56.

Th piston rod 56 of the infeed cylinder 46 is connected to the pusher block 52 to reciprocate the latter inwardly and outwardly. An adjusting screw 51 is connected to the outer extremity-of I the cylinder 46 by means of which the position of the cylinder 46 may be adjusted to properly position the pusher block 52.

The ejection cylinder 46 is mounted in a second inverted channel arm 58 which is supported from a hollow bracket casting 59 attached to the side of the work rest holder 2!. An ejector rod 68 extends longitudinally of the arm 58 and the cast- ,ing 59 and terminates in an ejection head 6| positioned to force the completed workpiece 54 from th work rest onto a receiving chute 62 which carries it from the machine.

The piston rod 56.0f the cylinder 46 is adjustably connected to the ejector rod 60 through the Fig. '7, it will contact can be understood from the above.

' type having a grinding medium of a toggle member 63 so thateach rean adjusting screw 64 by means of which the position of the entire assembly may be adjusted.

A rocking yoke 65 is mounted on a pivot pin 66 in the hollow bracket 59. One extremity of the yoke 65 is positioned opposite the ejection plunger 23 of the grinding machine. The other extremity thereof is forked to receive the ejector rod 68 so as to act against a set collar 61 thereon. This enables the operator to use the conventional ejector mechanism when desired, without interference with the automatic ejector mechanism.

It is believed that the operation of the device Briefly, the magazine 53 is filled with rough work pieces such as artillery shells, and the motors driving the grinding and feed wheels I l and I2 and the operating motor 25 are started. Let us now assume that one of the work-pieces is resting on the work rest 20. The rotation of the cam 29 will act on the feedsleeve IE to bring the feed wheel l2 against the work-piece so that the desired amount of material will be removed by the grinding wheel The cam 29 will now reverse the sleeve to with! draw the feed wheel l2 and simultaneously the cam 33 will contact the roller 39 so as to rotate the valve plug 36 to admit air under pressure from the pipe 4| to the outer extremities of the two cylinders 45 and 46. 'It will also simultaneously connect the inner extremities of these cylinders with the exhaust ports 44.

This causes the ejector head to force the finished work-piece from the rest 20 and also causes the pusher block to force the lowermost rough work-piece from the pile in the magazine 53 to a position between the wheels H and I2. The ejector head 6| temporarily supports the latter work piece and the pusher block 52 temporarily supports the pile of rough work pieces in the magazine 53.

The cam 33 now releases the roller 39 allowing the spring to return the valve plug 36 to its former position so as to connect the inner extremitiesof the cylinders and 46 with the compressed air pipe 4| and the outer extremities with the exhaust ports 44 so that both the pusher block 52 and the ejector head will be snapped outwardly. The cam 29 now brings the feed wheel l2 against the newly inserted work-piece. While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the. scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

l. A work-piece feeding and ejecting attachment for centerless grinding machines, of the wheel, a feed wheel and a work rest positioned between said wheels comprising: a horizontal in-ieed guide member extending into the space between said wheels above said Work rest; a magazine supporting a vertical ,pile of work-pieces on said guide member; a pusher block positioned to push the lowermost work-piece from said pile and from said guide member/so that it may fall by gravity to said work rest; a pneumatic cylinder; 9. piston in said cylinder; a piston rod extending from said piston to operating said valve from said latter device so that the movements of said valve will be in synchronism with the movements of said feed wheel; an ejector rod positioned on the opposite side block to actuate the latter; a two-way valve for alternately connecting the opposite ends of said cylinder with asource of fluid pressure; a cam shaft; a motor rotating said cam shaft; a first cam in said shaft; meansoperable by said first I cam formoving said feed. wheel toward and of the work rest from said pusher block in alignsecond pneumatic cylinder,- a second piston; a second piston rod connecting said second piston with said ejector rod for actuating the latter; and pneumatic conduits connecting said second cylinder with said valve so that the latter will control the ejection of the finished work pieces from said work rest.

2. A work-piece feeding and ejecting attachment for centerless grinding machines, of the type having a grinding wheel, a feed wheel and a work rest positioned between said wheels, comprising: a horizontal in-ieed guide member extending into the space between said wheels above said work rest; a magazine supporting a vertical ment with a work-piece resting on said rest; a

away from said grinding wheel; a second cam on said cam shaft; and means for actuatingvsaid valve'fromsaid second cam so that the changes in flow of said fluid pressure will be in synchronism with the movements of said feed wheel.

3. ,Awork-piec'e feeding and ejecting attachment for oenterless grinding machines, or the type having a grinding wheel, a feed wheel and'a work rest positioned between said wheels. comprising: pneumatically operated feeding means pile of work-pieces on said guide member; a,

pusher block positioned to push the lowermost work-piece from said pile and from said guide member so that it may fall by gravity to said work rest; a pneumatic cylinder; a piston in said cylinder; a piston rod extending from said piston toan operative connection with said pusher for placing a work piece on said work rest; a motor operated device for moving said feed wheel toward and away from said grinding wheel; a valve controlling said pneumatically. operated means; means for operating said valve from said motor operated device so that the movements of said valve will be synchronized with the movements of said feed wheel; a pneumatically operated ejecting means positioned on the opposite side of the work rest from the pneumatically operated feeding means and in alignment with a work-piece resting on said rest; and pneumatic conduits connecting said pneumatically operated ejecting means with said valve so that the latter will control the ejection of the finished work pieces from said work rest. JOHN E. HECKETHORN. 

